Classification of nonrigid motion in 3D images using physics-based vibration analysis

Presents a method for comparison and classification of nonrigid motion using a deformable model and the associated modal dynamics. Using the solid state physics formulation, the authors develop the equations of motion and the analytical expressions of vibration modes of a multidimensional elastically-deformable model that the authors use for tracking of nonrigid features in dynamic images. Thus, nonrigid motion of a 3D deformable object can be recovered in closed-form in modal space, by superimposing a few low-frequency modes that can be computed in a straightforward manner. The authors show that the deformation spectrum is a compact description of the deformation information, and allows deformation comparison and classification. Examples on 2D and 3D medical images are presented. The contribution of the paper is making modal analysis an efficient and easy-to-use tool for nonrigid motion classification